Research On Point-of-care Testing (POCT) For Nucleic Acid Based On Smartphone And Microfluidic Chip

In late 2019,the COVID-19 virus began to sweep the world.So far,the epidemic has caused huge economic losses and human casualties worldwide.Nucleic acid detection is the main tool for such viral epidemic diseases and plays a major role in epidemic prevention and control.Due to the long detection time,site and operational requirements of traditional nucleic acid detection,it is far from ideal for immediate prevention and control of viruses in the early stages of an epidemic.On the one hand,the length of traditional nucleic acid detection is 2 to 3hours,which does not allow for immediate detection of highly infectious viruses.On the other hand,the high technical and site requirements of traditional nucleic acid detection have led to the concentration of such detection in large hospitals,which is very unfriendly to detectors in remote areas.Moreover,in the early stages of an outbreak,detections concentrated in large hospitals are prone to cross-contamination.The loop-mediated isothermal amplification technique can effectively shorten the amplification time of nucleic acids and reduce the operational and instrumentation requirements.The use of this technology and the combination of microfluidic technology,image processing technology,mobile applications and other crosscutting technologies,each taking advantage of the strengths to achieve rapid,portable,automated point-of-care testing for nucleic acid has an important role to play.The point-of-care testing for nucleic acid platform based on smartphone and microfluidic chip,whose LAMP(loop-mediated isothermal amplification)system with color changes,combined with microfluidic chip is used for nucleic acid amplification,and color changes in the detection process are analyzed by cloud server,small program and image processing technology to judge detection results.Specifically,in the process of nucleic acid amplification,the color of sample solution changes from fuchsia to yellow,small program every 10 seconds pictures taken of the nucleic acid amplification area in a real time.At the same time,the cloud server receives this photo,then handle it to get G/B(green/blue)value from pixels of detection solution.The final G/B value curve of the amplification process is obtained,and platform analyzes this curve to get detection results.The whole process is done in a portable black box,which allows the detectors to log into the platform applet to complete the corresponding operation.Experiments on COVID-19 virus plasmids were carried out on this point-of-care testing for nucleic acid platform.The experimental results showed that the platform could make qualitative judgment on samples within 30 minutes and infer the initial concentration of samples with reference significance,the concentration can provide a basis for subsequent detection or research.Compared with traditional nucleic acid detection,point-of-care testing for nucleic acid carried out on this platform can remove site limitations of detection,reduce operating requirements,and shorten the testing time by 4/5.